In GSM (global system for mobile communications)/GPRS (general packet radio service)/EDGE (enhanced data rate for GSM evolution) networks, a number of common control channels are defined within the air interface between the mobile station (MS) and the base station transceiver (BTS). Common control channels (CCCH) and packet common control channels (PCCCH) support common procedures required to establish a dedicated link with the network. Typical channels include the RACH (Random Access Procedure), PCH (Paging Channel), and AGCH (Access Grant Channel) within GSM. In GPRS/EDGE, the common control channels include the PRACH (Packet Random Access Channel), PPCH (Packet Paging Channel) and PAGCH (Packet Access Grant Channel)
There are several paging subchannels in the same physical channel carrying the CCCH identified by a CCCH_GROUP or on the same PDCH carrying the PCCCH identified by a PCCCH_GROUP. The mobile station determines its own paging subchannel for paging block decoding according to the parameter PAGING_GROUP. This paging subchannel is defined as a set of multiframes carrying the CCCH or the PCCCH. Such set of multiframes defines the periodicity at which the mobile station is required to decode paging messages. There are two parameters used to determine such periodicity: BS_PA_MFRMS for the CCCH logical channels and SPLIT_PG_CYCLE for the PCCCH logical channels and, optionally, for the CCCH.
The BS_PA_MFRMS basically defines the number of 51-multiframes for the PCH periodicity. Its value is broadcasted on the BCCH and it can take values between 2 and 9.
The SPLIT_PG_CYCLE defines the occurrence of paging blocks on the PDCH carrying the PCCCH, or, optionally, on the CCCH, belonging to the mobile station in discontinuous reception (DRX) mode.
In order to minimize the power consumption, when in idle mode, the mobile station is not required to listen to all the (P)PCH logical channel occurrences. In DRX mode, the mobile station shall listen to the blocks corresponding to its paging group as defined by the different PAGING_GROUP values. In non-DRX mode, depending on whether there are or are not PCCCH channel(s) in the cell, the mobile station shall listen: to all blocks per multiframe where paging may appear on a PCCCH channel or to all blocks on a CCCH channel. Because the mobile station must undertake more listening in non-DRX mode, non-DRX mode utilizes more power and, thereby, consumes the battery of the mobile station more quickly.
Third generation partnership project (3GPP) standards specify five scenarios when the mobile station shall enter a non-DRX mode period (3GPP TS 44.060):                1. At the transition from packet transfer mode to packet idle mode, the mobile station shall enter the transfer non-DRX mode period.        2. At the transition from the dual transfer mode to the dedicated mode or packet idle mode, the mobile station shall enter the transfer non-DRX mode period.        3. A mobile station operating in network control cell reselection (NC2) mode shall enter the NC2 non-DRX mode period when it sends a network control (NC) measurement report.        4. When initiating the mobility management (MM) procedures for GPRS attach and routing area update defined in 3GPP TS 24.008, the mobile station shall enter the MM non-DRX mode period.        5. When mobile station receives a pre-notification for a multimedia broadcast/multicast service (MBMS) service and MBMS session, the mobile station shall enter the MBMS non-DRX mode.        
During a GPRS attach procedure, the mobile station requests values for the SPLIT_PG_CYCLE and NON_DRX_TIMER parameters to be applied on CCCH or PCCCH. Specifically, the NON_DRX_TIMER parameter controls the duration of the non-DRX mode period to be applied by the mobile station when it has left the packet transfer mode or the dual transfer mode and then enters the packet idle mode.
After a temporary block flow (TBF) release, the mobile station reverts to the non-DRX mode, in which it must decode all CCCH or PCCCH blocks, independently of its DRX period. This allows a faster downlink TBF establishment in the case the network needs to initiate a new downlink TBF, because it can send the downlink TBF allocation on any (P)CCCH related to the (P)CCCH_GROUP of the mobile station, and does not have to wait for the MS paging subchannel in order to send the paging message.
After a TBF release, the non-DRX period is equal to the minimum of the two following values: DRX_TIMER_MAX, set by the network and given on broadcast channels and NON_DRX_TIMER, set by mobile station during the GPRS attach procedure. The non-DRX timer may be set to account for a high probability that a new downlink TBF will need to be established a short time after the end of an uplink TBF, a downlink TBF, and/or both an uplink and a downlink running simultaneously. For instance, where the uplink TBF is used to send a request, a downlink TBF may be established for the transfer of the response. There may be a latency period between two consecutive internet protocol (IP) packets sent to a given mobile station. This means in some cases that several downlink TBFs are needed to send consecutive IP packets to the mobile station. The non-DRX mode has an impact on mobile station autonomy in idle mode because, in this period, the mobile station must continuously decode the CCCH or the PCCCH blocks.
FIG. 1 illustrates an example message flow between a mobile station 102 and a network 104. During a first time period, the network has established a downlink TBF 108 and the mobile station 102 is in packet transfer mode 106. During this time, the network sends, via the downlink TBF 108, a plurality of radio link control (RLC)/media access control (MAC) data packets including logical link control (LLC) data. A final packet sent from the network includes a final bit indicator (FBI) set to 1 to indicate that all data has been sent. After the FBI is received, the DL TBF is released and the non-DRX period 112 begins. The mobile station enters packet idle non-DRX mode 110 and the network enters non-DRX period 112. At the expiration of the non-DRX timer, the non-DRX mode period 110/112 ends and the mobile station enters packet idle DRX mode 114.
The nature of IP traffic usually leads to the frequent setup and release of the radio resources (more specifically TBFs), which results in increased signaling load and inefficiency in data transfer. In fact, setting-up and releasing a TBF takes significant time and radio resources. Unnecessary TBF setup and release can be avoided by delaying the release of the TBF using delayed DL TBF. More specifically, in the downlink direction, during an inactive period (e.g., when no data packets are waiting to be sent) the connection is maintained by periodically sending dummy LLC frames in the downlink direction.
In uplink direction, extended UL TBF procedures allow the UL TBF to be maintained during inactivity periods (when the MS does not have RLC information to send) and the network determines the release of the UL TBF. In contrast, in UL TBF non-extended mode, once the RLC output data queue reaches a specific threshold, a countdown procedure is initiated, and will lead to the release of the UL TBF even if new RLC blocks have to be sent after the countdown procedure started. Accordingly, a new UL TBF will need to be established to send any further RLC output data.